import socket
import os
import struct
from ctypes import *

host = "192.168.1.131"

class IP(Structure):
    _fields_ = [
        ("ihl", c_ubyte, 4),
        ("version", c_ubyte, 4),
        ("tos", c_ubyte),
        ("len", c_ushort),
        ("id", c_ushort),
        ("offset", c_ushort),
        ("ttl", c_ubyte),
        ("protocol_num", c_ubyte),
        ("sum", c_ushort),
        ("src", c_uint),
        ("dst", c_uint)
    ]
    def __new__(cls,  socket_buffer=None):
        return cls.from_buffer_copy(socket_buffer)
    
    def __init__(self, socket_buffer=None):
        
        # map protocol constants to their names
        self.protocol_map = {1:"ICMP", 6:"TCP", 17:"UDP"}
        
        # human readable IP addresses
        self.src_address = socket.inet_ntoa(struct.pack("<L",self.src))
        self.dst_address = socket.inet_ntoa(struct.pack("<L",self.dst))
        
        # human readable protocol
        try:
            self.protocol = self.protocol_map[self.protocol_num]
        except:
            self.protocol = str(self.protocol_num)

if os.name == "nt":
    socket_protocol = socket.IPPROTO_IP
else:
    socket_protocol = socket.IPPROTO_ICMP

sniffer = socket.socket(socket.AF_INET, socket.SOCK_RAW, socket_protocol)

sniffer.bind((host, 0))
sniffer.setsockopt(socket.IPPROTO_IP, socket.IP_HDRINCL, 1)

if os.name == "nt":
        sniffer.ioctl(socket.SIO_RCVALL, socket.RCVALL_ON)

try:
    while True:
        # read in a packet
        raw_buffer = sniffer.recvfrom(65565)[0]
        
        # create an IP header from the first 20 bytes of the buffer
        ip_header = IP(raw_buffer[0:20])
        # print out the protocol that was detected and the hosts
        print "Protocol: %s %s -> %s" % (ip_header.protocol,ip_header.src_address,ip_header.dst_address)

# handle CTRL-C
except KeyboardInterrupt:
        # if we're using Windows, turn off promiscuous mode
        if os.name == "nt":
            sniffer.ioctl(socket.SIO_RCVALL, socket.RCVALL_OFF)